<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .f {
      border: 10px solid #000;
      min-height: 10px;
      /* overflow: hidden; */
      /* display: inline-block; */
      /* float: left; */
      /* position: absolute; */
      /* display: flow-root; */
    }
    .s {
      height: 200px;
      width: 400px;
      /* float: left; */
      background: skyblue;
      margin: 20px 0
    }
    /* .sun {
      width: 100px;
      height: 300px;
      background: orange;
      float: left;
    } */
  </style>
</head>
<body>
  <div class="f">
    <div class="s">
    </div>
    <div class="s" style="margin-top: 30px;">
    </div>
  </div>
</body>
</html>